Owning a home in Canterbury has become 10.6 per cent less affordable in the past year despite record levels of house construction, new research shows.

Massey University's latest affordability report revealed the region was the third least affordable for home ownership, behind Auckland and Queenstown lakes, with Nelson-Marlborough fourth. Southland is the most affordable.

The affordability is calculated by Massey University for each region, comparing average weekly household earnings against the median house price and mortgage interest rates.

Homes nationally became 7.6 per cent less affordable over the year.

Massey's researchers said the results were ''no real surprise'' as wage rises were not enough to offset increasing house prices and interest rates.

''This deterioration in affordability is likely to continue as recent interest rate increases are incorporated into the debt servicing costs for home mortgages,'' they said.

The researchers noted that the affordability gap between urban and rural regions was widening.

Canterbury had the second worst slide in affordability in the country of the 12 regions, behind the Queenstown lakes area, with Auckland third.

Real estate figures put the median Canterbury-Westland house price at over $400,000, with market observers expecting no let-up in housing inflation while the shortage persists.

Meanwhile the latest consent figures from Statistics New Zealand show 605 homes got building consent in Canterbury last month, including 46 apartments.

This was up from 494 in May last year, and the most for any month since the start of electronic records in 1990.

The average value of the homes approved was $322,000, not including land, up from $311,000 a year ago.